Rotary table device

Abstract

There is provided a rotary table device including: a rotary table; a center shaft erected toward the rotary table; a housing including an inner peripheral surface having a circular cross section over a predetermined range along a rotation axis; a center sleeve including an outer peripheral surface having a circular cross section corresponding to the inner peripheral surface, and the outer peripheral surface being concentric with the inner peripheral surface; a plurality of recesses formed in at least one of the inner circumferential surface and the outer circumferential surface; a plurality of O-rings disposed to be sandwiched between the inner peripheral surface and the outer peripheral surface; an in-housing fluid flow path formed inside the housing; and a plurality of in-sleeve fluid flow paths formed inside the center sleeve.

What is claimed is: 
     
       1. A rotary table device comprising:
 a rotary table; 
 a case supporting the rotary table rotatably around a rotation axis; 
 a center shaft erected toward the rotary table in a position of the case corresponding to the rotation axis; 
 a housing fixed to the case and spaced apart from the center shaft to surround the center shaft, the housing including an inner peripheral surface having a circular cross section over a predetermined range along the rotation axis; 
 a center sleeve disposed outside the center shaft and inside the housing, the center sleeve being fixed to the rotary table, the center sleeve including an outer peripheral surface having a circular cross section corresponding to the inner peripheral surface, and the outer peripheral surface being configured to rotate concentrically with the inner peripheral surface; 
 a rotary encoder disposed on the center shaft and the rotary table, the rotary encoder being configured to detect a rotation angle of the rotary table; 
 a plurality of recesses formed in at least one of the inner peripheral surface and the outer peripheral surface to form a flow path of a fluid; 
 a plurality of O-rings disposed to be sandwiched between the inner peripheral surface and the outer peripheral surface to prevent a leakage of the fluid from the plurality of recesses; 
 an in-housing fluid flow path formed inside the housing and each communicating with the plurality of recesses; 
 a plurality of in-sleeve fluid flow paths formed inside the center sleeve and each communicating with the plurality of recesses to supply the fluid into the flow path provided in the rotary table; and 
 a gap is formed between an outer surface of the center shaft and an inner surface of the center sleeve along an entire length of the center sleeve. 
 
     
     
       2. The rotary table device according to  claim 1 ,
 wherein the plurality of recesses have an annular groove shape. 
 
     
     
       3. The rotary table device according to  claim 1 ,
 wherein the plurality of recesses are formed on the inner peripheral surface of the housing. 
 
     
     
       4. The rotary table device according to  claim 1 , further comprising:
 a rotary support portion arranged between the center shaft and the center sleeve. 
 
     
     
       5. The rotary table device according to  claim 4 ,
 wherein the rotary support portion includes a bearing device or a dry bush. 
 
     
     
       6. The rotary table device according to  claim 1 , wherein no seals are disposed in the gap between the center shaft and the center sleeve.